Advance warning system for railroad crossing

ABSTRACT

An early warning system warns a motorist that a train is near a railway crossing that is being approached by the motorist. The early warning system utilizes magnetometers that are placed along a railway at locations corresponding to the locations at which existing electrical circuits detect an approaching train. The early warning system also includes a sign system that is spaced apart from the railway crossing and is visible to a driver at least five hundred feet before the driver reach the sign system. The sign system is activated when a train approaches the railway crossing.

This invention pertains to alarm and warning systems.

More particularly, the invention relates to a system for warning a motorist that a train is near a railway crossing that is being approached by the motorist.

Active protection railroad crossings comprise railroad crossings that incorporate electrical circuits on the railway tracks and include signs equipped with lights that flash, include bells, or include gates that open and close. The electrical circuits are known as “C” circuits and predictor circuits and these circuits activate the lights and cause the lights to flash, activate the bells, and/or activate and close the gates when a train approaches the crossing. The electrical circuits are configured to detect an approaching train at locations along the railway track that are each a specified distance from a railroad crossing; for example, at 2000 feet, 1500 feet, 1000 feet, 500 feet, and 300 feet from the railroad crossing. The functioning of such electrical circuits often is not reliable because inclement weather such as rain or snow can cause the circuits to malfunction when a train approaches.

Passive protection railroad crossings comprise crossings which do not have electrical circuits, which do not have lights or bells or gate, and which have only a sign.

Each year, fatalities occur at railway crossings when a train accidentally strikes a vehicle or vice-versa. One cause of such accidents is that some sections of a railway are elevated above portions of roads that approach the railway. The road is, until it reaches the railway crossing, at an elevation below the railway crossing. Once the road nears the railway, the road rises or slopes up from its normal elevation to the elevation of the railway, and then, after crossing the railway, falls or slopes down from the elevation of the railway back to the normal elevation of the road. As a result, an approaching motorist often does not realize that he or she is approaching a railway until the motorist is on-top-of or is nearly on-top-of the railway. This, practically speaking, gives the motorist no time to stop in the event a train is approaching and arrives at the crossing simultaneously with the motorist.

Another cause of railway crossing accidents is that a railway crossing is located shortly after a curve in a road so that a motorist does not see the crossing until he or she comes around the curve. As a result, the motorist does not have sufficient time to stop in the event a training is approaching or is at the crossing. The fact that there is a railroad crossing sign or are warning lights at the crossing often does not prevent such accidents, especially when the crossing is at the top of a hill, when the crossing occurs up shortly after a motorist navigates a curve in the road, or when fog or rain or snow obscures the crossing.

Accordingly, it would be highly desirable to provide improved apparatus to warn a motorist of the approach of a train.

Therefore, it is a principal object of the invention to provide improved system for warning a motorist that a train is approaching.

Another object of the invention is to provide improved apparatus to warn a motorist of the onset of a railroad crossing that is located at the crest of a hill or that is located soon after a curve in a road.

These and other, further and more specific objects and advantages of the invention will be apparent from the following detailed description of the invention, taken in conjunction with the drawings, in which:

FIG. 1 is a perspective view illustrating a warning system constructed in accordance with the principles of the invention; and,

FIG. 2 is a schematic diagram illustrating one embodiment of the warning system of the invention.

Briefly, in accordance with my invention, I provide an improved warning system for a railroad crossing consisting of the intersection of a road and a railway. The warning system alerts a driver of a vehicle approaching along the road the railroad crossing of the presence of a train on the railway. The warning system comprises at least one sensor to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; at least one warning sign system positioned along the road at least one hundred feet from the railroad crossing to receive activation signals and including a railroad crossing warning sign, a spaced apart pair of lights that each are normally off and that flash on and off when the sign system receives the activation signals, and a sign indicating that a train is approaching when the lights flash. The warning sign is visible to the driver of the vehicle on the road and approaching the railroad crossing at least five hundred feet before the vehicle reaches the warning sign system under weather conditions where visibility is at least five hundred feet. The sensor can cause activation signal to be produced by sending warning signals to a controller that receives the warning signals and generates the activation signals. There can be a direct line of sign from the warning sign system to the railroad crossing. The can be a plurality of sensors to detect the location of the train at different points along the railway. The sensor can determine the speed of the train. The sensor can be a magnetometer. The sensor can determine the distance of the train from the railroad crossing. The sign system can include only a single light that flashes when the sign system receives the activation signals. The warning signals can be transmitted as radio signals. The flashing lights can each have a width of at least eight inches. The flashing lights can alternately flash on and off.

In another embodiment of the invention, I provide an improved warning system for a railroad crossing consisting of the intersection of a road and a railway. The system alerts a vehicle approaching along the road the railroad crossing of the presence of a train on the railway. The system comprises at least one sensor in the railway to measure a magnetic field to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; and, a warning sign system positioned along the road at least one hundred feet from the railroad crossing to receive the activation signals and including a railroad crossing warning sign, at least one signal light to flash on and off when the sign system receives the activation signals, and a sign indicating that a train is approaching when the lights flash. The warning sign is visible to the driver of the vehicle on the road and approaching the railroad crossing before the vehicle reaches the warning sign system.

In a further embodiment of the invention, I provide an improved warning system for a railroad crossing consisting of the intersection of a road and a railway. The system alerts a vehicle approaching along the road the railroad crossing of the presence of a train on the railway. The system comprises at least one sensor in the railway to measure a magnetic field to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; and, a warning sign system positioned along the road at least one hundred feet from the railroad crossing and with a direct line of sight to the railroad crossing to receive the activation signals. The warning sign system includes a railroad crossing warning sign; at least one signal light to flash on and off when the sign system receives the activation signals; and, a sign indicating that a train is approaching when the lights flash. The warning sign is visible to the driver of the vehicle on the road and approaching the railroad crossing before the vehicle reaches the warning sign system.

Turning now to the drawings, which depict the presently preferred embodiments of the invention for the purpose of illustrating the practice thereof and not by way of limitation of the scope of the invention, and in which like reference characters refer to corresponding elements throughout the several views, FIG. 1 illustrates the presently preferred embodiment of the invention. Road 21 and railway 31 intersect at railroad crossing 30. A standard railroad crossing sign 13 is located at the railroad crossing. Sign 13A is an enlarged view of sign 13 and includes conventional railroad crossing “X” sign and includes a pair 19 of lights that, when activated, flash. Sign 13, even if it includes lights 19 that are activated and flashing, often will not prevent a motorist—train collision at crossing 30, particularly when crossing 30 is at the crest of a hill, when crossing 30 is located shortly after a curve in road 21, or when crossing 30 is in a “white-out” condition and is not visible in fog or snow or rain until a motorist is at the crossing 30.

Sensors 11 and 12, preferably magnetometers, are placed along railway 31 at designated intervals before crossing 30 to detect a train approaching crossing 30 in the direction of arrow A. A magnetometer measures the intensity of the earth's magnetic field and detects changes that occur in the field when a metal object like a train locomotive passes through the earth's magnetic field. Utilizing detection apparatus that measures the earth's magnetic field is an important feature of the invention. Such detection apparatus is more reliable than conventional electric current sensing apparatus and has evidently not been utilized to detect the approach of a train or in combination with apparatus that generates signals activating a warning sign.

The location of sensors 11, 12 along railway 31 can vary as desired. Presently, sensors typically are located at 2000 feet, 1500 feet, 1000 feet, 500 feet, and 300 feet from crossing 30. When the system of the invention is utilized at a railroad crossing that has pre-existing active protection (in the form of the electrical circuits earlier referred to) or that has active protection installed along with the system of the invention, sensors 11, 12 are located at detection points or locations along railway 31 that correspond to the locations at which the electrical circuits are configured to detect the presence of a train. Consequently, if the electrical circuits at a crossing with active protection are configured to detect the presence of a train at 2000 feet, 1500 feet, 1000 feet, 500 feet, and 300 feet from crossing 30, then sensors 11, 12 are placed along railway 31 at corresponding distances of 2000 feet, 1500 feet, 1000 feet, 500 feet, and 300 feet from crossing 30. Such correspondence of the location of sensors 11, 12 with the same locations along railway 31 at which existing electrical circuits detect the presence of an approaching train is unexpected and redundant. Although contraindicated, such redundance is, however, an important feature of the invention because it compensates for unreliable electrical circuits, significantly reduces the risk that a vehicle will be struck by a train, and significantly reduces the potential liability of the railroad company. Further, conventional or other control circuitry and systems associated with existing electrical circuits at a railroad crossing can be used in the system of the invention to reduce the cost of installing the system of the invention. For example, the conventional control circuitry can, instead of being activated only by the electrical circuits associated with the railway, be operatively associated with and activated by the sensors used in the invention. Such conventional control circuitry functions to activate warning lights, bells, and/or gates at the crossing when a train approaching the crossing is detected a selected distance(s) from the railroad crossing.

A sensor 11, 12 located at 2000 feet from the railroad crossing typically will detect a train at least twenty seconds before the train reaches crossing 30, provided the train is traveling at no more than a speed limit of sixty-five miles an hour. If the train is traveling at a greater speed limit, the distance from crossing 30 of the first sensor can be increased until at least twenty seconds passes from the time that the train is detected until the train reaches the crossing 30. The advance detection zone includes a portion of the railway 1,001 feet to 2,000 feet from crossing 30. The motion detection zone includes a portion of the railway that is 301 feet to 1,000 feet from crossing 30. The presence detection zone includes a portion of the railway 31 that is three hundred feet or closer to crossing 30.

Each sensor 11, 12 can, in addition to generating and transmitting warning signals when it detects a train, generate and transmit signals that define the speed of the train and the distance of the train from crossing 30. The warning signals from a sensor 11, 12 are transmitted from the sensor to a control unit 10. Control unit 10 generates activation signals that are transmitted to the warning sign system 14. If desired, control unit 10 can be eliminated or combined with system 14 or with a sensor 11, and the warning signals from a sensor 11, 12 can comprise activation signals that are transmitted directly to system 14.

Sign system 14A is an enlarged depiction of sign 14. Sign system 14A (and 14) includes a sign 18 stating “TRAIN APPROACHING WHEN FLASHING”, includes a conventional circular “X” railway crossing (RR) warning sign; and includes a stacked, spaced apart pair of warning lights 15 and 16. The size of warning lights 15 and 16 can vary, but each light is preferably at least eight inches wide in diameter. The lights can, when activated, be continuously on; however, the lights 15 and 16 each preferably flash on and off. Further the lights preferably alternately flash on and off, i.e., when light 15 is on then light 16 is off, and vice-versa. While a single light 15, 16 can be utilized, the use of a pair of spaced apart vertically stacked (or horizontally spaced apart) lights is believed important in the invention to insure that it is likely a motorist will notice the sign system 14 and will notice the signs 17 and 18 intermediate or otherwise adjacent lights 15 and 16. If only a single light 15 is utilized, the light 15 can be continuously on and need not flash on and off when activated. A single light 15 does, however, preferably flash on and off when activated.

Sign 17 can be a first sign placed along road 21, sign 18 can be a second sign spaced apart from the first sign, and the flashing lights 15 and 16 can comprise a third sign placed along road 21 separate and spaced apart from the first sign. Or sign 17 and lights 15 and 16 can be combined in one sign and sign 18 can be a separate sign, and so on. It is, however, preferred to combine signs 17 and 18 and lights 15 and 16 in the manner shown in FIG. 1 so a motorist can take in at a single glance all the information in sign system 14.

The positioning of sign system 14 along a road 21 is important. According to the invention, the first criteria in placing sign system 14 is, if possible, to insure that a motorist on road 21 has a clear line of sight and can see the sign system 14 from at least 500 feet away (assuming weather conditions permit visibility of at least 500 feet) as the motorist approaches sign system 14. Giving a motorist adequate time to see and comprehend sign system 14A is important in the system of the invention. The second criteria in placing sign system 14 is, if possible, to place sign system 14 at least one hundred feet, preferably one hundred and fifty feet, most preferably 300 to 1000 feet, from crossing 30 such that there is a direct line of sight from system 14 to crossing 30. Placing system 14 closer than one hundred feet, preferably no closer than one hundred and fifty feet, to crossing 30 often does not give a motorist sufficient time to react to and stop his or her vehicle before reaching the crossing. If it is not possible to permit a motorist to see system 14 at least 500 feet before the motorist reaches system 14 while traveling along road 21, then it is preferred that two or more sign systems 14 be utilized to give a motorist time to see and comprehend signs 17 and 18.

It is possible, of course, that a motorist will be intermediate sign 13 and sign system 14 when the system of the invention first detects the approach of a train and activates sign system 14, in which case the motorist has to rely on sign 13. However, in such an event the motorist will still, in many cases, reach and safely make it past crossing 30 ahead of the train.

Operation of the system of the invention is described with reference to FIGS. 1 and 2. Sensors 11, 12 are installed along railway 31. Control 10 is installed near, at, or remote from crossing 30. At a railway crossing with active protection, the pre-existing control circuitry that is already installed at the railway crossing and is associated with the electrical circuits in railway 31 can, as noted earlier, be utilized to reduce the cost of installation of the system of the invention. Each sensor 11, 12 is connected to such existing control circuitry such that when a sensor 11, 12 detects an approaching training, the sensor generates a signal to the control circuitry that causes the control circuitry to activate the lights, bells, and/or gates at the crossing. Sensors 11, 12 are located along railway 31 at 2000 feet, 1500 feet, 1000 feet, 500 feet, and 300 feet from crossing 30. The sensor at 2000 feet from crossing 30 is in the advance detection zone. The sensors at 1500, 1000, and 500 feet from crossing 30 are in the motion detection zone. The sensor 300 feet from crossing 30 is in the presence detection zone.

Warning sign system 14 is installed along road 21 such that a motorist traveling in right hand lane 22 has a clear line of sight to and can see system 14 at least 500 feet (assuming the existing weather produces visibility of at least 500 feet) before the motorist reaches system 14. System 14 also is preferably at least one hundred and fifty feet from crossing 30, and is at a location from which there is a direct line of sight to crossing 30. There is a direct line of sight if the motorist can see the crossing through the front windshield of his vehicle when the vehicle is on road 21 adjacent sign system 14.

While a motorist is traveling along right hand lane 22 or road 21 toward sign 14, a locomotive leading a train that is moving along railway 31 toward crossing 30 reaches and is detected by the sensor 42 that is 2000 feet from crossing 30. The sensor 42 is in the advance detection zone and generates warning signals and transmits the signals to control 40 and to advance data 49 in memory 41 of unit 10. Advance detection sub-routine 45 of control 40 generates activation signals to the warning sign system 14 (53 in FIG. 2). Lights 15 and 16 begin to alternately flash on and off. The motorist (not shown) traveling along the right hand lane 22 sees the flashing lights 15 and 16, reads signs 17 and 18, and (normally) automatically begins slowly reducing the speed of travel of his or her vehicle.

The locomotive leading the train reaches and is detected by the sensor 42 that is 1500 feet from crossing 30. Sensor 42 is in the advance detection zone and sends signals to control 40 and to advance data 49 in memory 41. Advance detection sub-routine 45 of control 40 permits lights 15 and 16 to continue flashing unless more than thirty seconds (or some other designated time period) has elapsed since the sensor at 2,000 feet from crossing 30 first detected the train. If thirty seconds elapses after the sensor 42 at 2000 feet from the crossing 30 detects the train and before the sensor at 1500 from the crossing detects the train, motion sub-routine 46 of control 40 sends deactivation signals to sign system 14 that cause lights 15 and 16 to stop flashing and to turn off.

The locomotive leading the train reaches and is detected by the sensor 43 that is 1000 feet from crossing 30. The sensor 43 is in the motion detection zone and generates and sends signals to control 40 and to motion data 50 in memory 41. If less than thirty seconds (or some other designated time period) has elapsed since the sensor 42 at 2000 feet detected the train, motion sub-routine 46 of control 40 permits lights 15 and 16 to continue flashing. If thirty seconds elapses after the sensor 42 at 2000 feet from the crossing 30 detects the train and before the sensor at 1000 from the crossing detects the train, motion sub-routine 46 of control 40 sends deactivation signals to sign system 14 that cause lights 15 and 16 to stop flashing and turn off. For sake of this example, less than thirty seconds elapses from when the sensor at 2000 feet from crossing 30 detects the train to when the sensor at 1000 feet from the crossing 30 detects the train. Therefore, lights 15 and 16 continue to flash. Signals from control 10 to system 14 can be radio signals, can be other wireless signals, can be sent along a fiber optic cable, or can be transmitted by any other desired means, as can signals from sensors 11 and 12.

The locomotive leading the train reaches and is detected by the sensor 43 that is 500 feet from crossing 30. The sensor 43 is in the motion detection zone and sends signals to control 40 and to motion data 50 in memory 41. Motion sub-routine 46 of control 10 permits lights 15, 16 to continue flashing unless more than ten seconds has elapsed since the sensor 43 at 1,000 feet from crossing 30 first detected the train. If ten seconds elapses after the sensor 43 at 1,000 feet from the crossing 30 detects the train and before the sensor 43 at 500 feet from the crossing detects the train, motion sub-routine 46 of control 40 sends deactivation signals to sign system 14 that cause lights 15 and 16 to stop flashing and turn off. For sake of this example, less than ten seconds elapses between activations of the sensor 43 at 1000 feet and the sensor 43 at 500 feet. Therefore, lights 15 and 16 continue to flash.

The locomotive leading the train reaches and is detected by the sensor 44 that is 300 feet from crossing 30. If less than ten seconds (or some other designated time period) has elapsed since the sensor 44 at 500 feet detected the train, presence sub-routine 47 of control 40 permits lights 15 and 16 to continue flashing. If ten seconds elapses after the sensor 43 at 500 feet detects the train and before the sensor 44 located 300 feet from crossing 30 detects the train, presence sub-routine 47 of control 40 sends deactivation signals to sign system 14 that cause lights 15 and 16 to stop flashing and turn off. For sake of this example, less than ten seconds elapses between activations of the sensor 43 at 500 feet and the sensor 44 at 300 feet. Therefore, lights 15 and 16 continue to flash.

Eight seconds (or some other designated period of time) after the sensor 44 that is 300 feet from the crossing detects the train, exit sub-routine 48 of control 40 sends deactivation signals to system 14 that cause system 14 to turn off lights 15 and 16. Sub-routine 48 can also send out deactivation signals eight seconds after the sensor 44 at 300 feet detects the last car in the train.

Having described my invention in such terms as to enable those of skill in the art to make and practice it, and having described the presently preferred embodiments thereof, 

1. A warning system for a railroad crossing consisting of the intersection of a road and a railway, the system alerting a driver of a vehicle approaching along the road the railroad crossing of the presence of a train on the railway, said system comprising (a) at least one sensor to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; (b) at least one warning sign system positioned along the road at least one hundred and fifty feet from the railroad crossing to receive activation signals and including (i) a railroad crossing warning sign, (ii) a spaced apart pair of lights that each are normally off and that flash on and off when said sign system receives said activation signals (ii) a sign indicating that a train is approaching when said lights flash,  said warning sign visible to the driver of the vehicle on the road and approaching the railroad crossing at least five hundred feet before the vehicle reaches the warning sign system under weather conditions where visibility is at least five hundred feet.
 2. The warning system of claim 1 wherein the sensor causes activation signals to be generated by sending warning signals to a controller that receives said warning signals and generates said activation signals.
 3. The warning system of claim 1 wherein there is a direct line of sign from said warning sign system to said railroad crossing.
 4. The warning system of claim 1 wherein there are a plurality of said sensors to detect the location of the train at different points along the railway.
 5. The warning system of claim 1 wherein said sensor determines the speed of the train.
 6. The warning system of claim 1 wherein said sensor is a magnetometer.
 7. The warning system of claim 1 wherein said sensor determines the distance of the train from the railroad crossing.
 8. The warning system of claim 1 wherein said sign system includes only a single light that flashes when said sign system receives said activation signals.
 9. The warning system of claim 5 wherein said warning signals are transmitted as radio signals.
 10. The warning system of claim 1 wherein said flashing lights each have a width of at least eight inches.
 11. The warning system of claim 1 wherein said flashing lights alternately flash on and off.
 12. The warning system of claim 1 wherein said railroad crossing includes an existing electrical circuit system that detects the presence of a train at said selected distance from said crossing.
 13. A warning system for a railroad crossing consisting of the intersection of a road and a railway, the system alerting a vehicle approaching along the road the railroad crossing of the presence of a train on the railway, said system comprising (a) at least one sensor in the railway to measure a magnetic field to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; (b) a warning sign system positioned along the road at least one hundred and fifty feet from the railroad crossing to receive said activation signals and including (i) a railroad crossing warning sign, (ii) at least one signal light to flash on and off when said sign system receives said activation signals (ii) a sign indicating that a train is approaching when said lights flash,  said warning sign visible to the driver of the vehicle on the road and approaching the railroad crossing before the vehicle reaches the warning sign system.
 14. A warning system for a railroad crossing consisting of the intersection of a road and a railway, the system alerting a driver of a vehicle approaching along the road the railroad crossing of the presence of a train on the railway, said system comprising (a) at least one sensor in the railway to measure a magnetic field to detect the presence of a train on the railway a selected distance before the railroad crossing and to generate activation signals; (b) a warning sign system positioned along the road at least one hundred and fifty feet from the railroad crossing and with a direct line of sight to the railroad crossing to receive said activation signals and including (i) a railroad crossing warning sign, (ii) at least one signal light to flash on and off when said sign system receives said activation signals, (ii) a sign indicating that a train is approaching when said lights flash,  said warning sign visible to the driver of the vehicle on the road and approaching the railroad crossing before the vehicle reaches the warning sign system. 